Washington State Building Code Shed Permit Threshold

Under RCW 19.27.031 and chapter 51-51 WAC, Washington adopts the International Residential Code (IRC) as the statewide residential building code. IRC Section R105.2 exempts one-story detached accessory structures of 200 square feet or less from building permits, although electrical, plumbing, and zoning rules still apply. Local jurisdictions may not adopt residential code amendments less stringent than the state code, but may impose additional zoning setback requirements. Electrical permits are administered by the Department of Labor and Industries under RCW 19.28.

Building without a required permit can trigger stop-work orders and double permit fees under local enforcement of the state code.